DE19829710A1 - Fully automatic method of harmonization of line of sighting device and homing head in weapon system installed on aircraft - Google Patents

Abstract

Steering angle for the alignment of the homing head is determined fully automatically where an image processor records and stores any deviations to provide correction values. The lines of sight of the sighting device and the homing head intersect at the target on the ground. An Independent claim includes an apparatus for preparation for fully automatic harmonization of the lines of sight of a sighting device and a homing head in a weapon system.

Description

The present invention relates to a method of preparation the fully automatic harmonization of the lines of sight of the visor and search head of a weapon system set up on an aircraft.

Conventionally, the lines of sight of the visor and are harmonized Search head for a hub that is set up on an aircraft screwdriver-based weapon system manually. One with a mark target plate built. It should be big enough to do that Field of view of both the visor and that used for harmonization Seeker head replica (SKN) because the principle of manual Harmonization on the parallel line of sight of the sight and seeker head replica based. In a first step, the operator / shooter does this Aim at a suitable marker to represent the target. At known distances (horizontal and vertical) from the sight and the launcher tube the target position of the seeker head line of sight can be unloaded case (no seeker head replica in the launcher tube) on the target plate teln. Then the launcher tube is loaded with the seeker head replica and with an alignment laser attached to the launcher the current position of the seeker head line of sight from Setpoint determined.  

However, such conventional methods and devices have Determination of the control angle for the harmonization of the lines of sight of Visor and seeker head in a helicopter-based weapon system straight thereby a disadvantage in that the harmonization is manual takes place and is therefore very time-consuming and inaccurate.

The invention is therefore based on the object of a method and a Device for preparing the fully automatic harmonization of the Lines of sight of the visor and seeker head on on an aircraft aimed weapon system to create the harmonization fully automatically and enables with high accuracy.

According to the invention, this object is achieved by the features of the patent 5 or 1 solved. Further advantageous configurations are in the Subclaims specified.

This is a fully automatic and precise harmonization of the lines of sight from the visor and seeker head at a helicopter-based weapon system enough.

Other objects, advantages and features of the present invention the from the following description of a preferred embodiment obviously in connection with the drawing.

Show it:

Fig. 1 schematic representation of the squint angle ψ _squint in azimuth and

Fig. 2 schematic representation of the squint angle θ _squint in elevation.

A long-term operational readiness of a weapon system is often indicated Carrier helicopters required. To achieve this, mechanical Tolerances between the visor attached to the carrier and the throwers flanged to the carrier with a Muniti located therein replica (in weight and size like a real missile) be averaged and compensated for the briefing process in the battlefield ensure. The briefing is a process in which the search head of the missile, for example a PARS3 missile or an ATA Ammunition aimed at the target sighted on.

According to the invention, a specially provided harmonization process major, to which the present inventive method belongs, fully automatic done table.

The basic principle of harmonization is as follows. The sight one on the Ground-mounted helicopter is placed on a truck approx. 100 m away aligned. The search head replica should now also be on the same Target point to be aligned. Usually mechanical tolerances are only partially successful. The deviations that occur are registered and stored by an image processing unit. she serve as correction values in later use.

The method according to the invention enables execution this principle of harmonization, in particular the determination of the drive  angle for aligning the search head replica to fully automatic Wise. In particular, there has so far been no possibility of harmonization The line of sight of the sight and seeker head replica in the target for short Bring distances (approx. 50 m to 100 m) to the intersection.

Based on the measurement configuration (rest position of the carrier helicopter on the ground, position of an artificial target approx. 100 m away from the Carrier helicopter, mast tilt of the visor flange, launcher position) are first of all by means of geometric relations and corresponding coor dinate transformations the input variables for a parallelization unit determined. By processing the input variables for the parallelism is caused that the output values of the parallelization unit, the so-called control angle, the line of sight of the seeker head replica align the target at the intended distance.

Then if the line of sight of the seeker head replicates with the line of sight cuts the sight in the target, there are no longer any tolerances. Others if there are mechanical tolerances that are from image processing can be recognized.

Before being fed to the parallelization unit, the input variables become one Processing device supplied, which process the input variables in this way tet that instead of a parallelization of the lines of sight a convergence of the Line of sight is reached.  

The processing unit calculates the squint angle, ie the angle at which a sight would look at the target object at the location of the seeker head replica (SKN). The following requirements are assumed for this calculation:

• 1. The plane on which the target and helicopter are standing is in good condition Approximation flat and without gradient.
• 2. The distance of the target plane from the helicopter is known, as well the mast tilt of the visor.
• 3. The helicopter is oriented so that its longitudinal axis covers the surface of the target scope.
• 4. All angles for the calculations are in rad.
• 5. The coordinate system used by the briefing processor (AP) corresponds to the agreements of the information sheet aviation standard LN 9300.

In Figs. 1 and 2 is a projection onto the (110) plane (xy plane) in the azimuth (Fig. 1) and elevation (Fig. 2) is shown, which represents these conditions, the flow into the calculation of the squint angle . Here, designated ψ 1 _Schiel the lateral deflection net in Fig. The squint angle in azimuth, ψ _VF the angle between the optical axis of the visor (OAV) or sighting camera and the visor and flange Dy _truck of the visor in the target plane. Furthermore, in Fig. 2 θ _Schiel the squint angle in elevation, θ _VF the angle between the optical axis of the visor (OAV) or visor camera and the visor flange and Δz _truck the vertical deflection of the visor in the target plane. The zero point of the reference coordinate system is fixed in the sights, the alignment of the axis is parallel to that of the carrier.

In this representation according to FIGS. 1 and 2, the optical axis of the visor can be viewed as an arrow which rotates in a spherical shell (circle with a solid line) around the visor head in azimuth and elevation. This arrow penetrates the image plane at a distance L (L = distance from the sight to the target), namely where the target object is located. At the location of the search head replica, i.e. by ΔL in the x direction (ΔL = difference between the distances sight-target and seeker replica-target), by d _Az or -d _Az in the y direction (d _Az = distance sight-seeker replica in y - Direction) and offset by d _El in the z direction (d _El = distance between the sight and seeker head formation in the z direction), there should now be a second, imaginary sight, the optical axis of which, again as a rotating arrow, also includes the image plane pierced at the location of the target object (circle with dashed line). The model of an imaginary sight comes from the question: At what angle would a sight look at the target object at the location of the seeker head replica? These angles represent the so-called squint angles.

This fact can be formulated on the basis of appropriate turning matrices. The matrices generally have the following form:

The coordinate system required for the calculation of the squint angle is stored with its origin in the visor head of the real visor and looks towards (1,0,0) ^T , i.e. in the x-direction of the helicopter's longitudinal axis. For the real visor, taking into account the mast inclination θ _M (= angle of the visor mast inclination) (= -4 ° = -0.0698 rad) and the gimbal angle (angle between the visor camera and the visor flange) gilt _VF and θ _VF (in azimuth or . Elevation) from the target the following transformation equation:

or accordingly

The index T stands for the transpose. L 'denotes the radius of one Bullet around the real sight, the shell of which is the target object at a distance L (L '≧ L) pierces. After multiplying out, equation (1b) obtains the following Shape.  

The first component of the vector, the distance of the penetration point in the target plane, is known and equal to L. This also results in L ', and the components y and z. In summary, this means:

The position of the imaginary visor is shifted from the coordinate origin of the real visor by the translation vector. In the case of a translation, a vector in the coordinate system of the real visor transforms into a vector in the coordinate system of the imaginary visor in accordance with equation (4):

_imag.visier = _real.Visier - (4)

In the present case, the displacement vector

The following applies to sign (d _Az ):

The intersection of the spherical shell of the imaginary visor and the spherical shell of the real visor takes place in the target plane at the location of the target object (x, y, z) ^T. The following transformation equation results for the imaginary sight at the position of the seeker head replica, where L '' denotes the radius of the sphere around the imaginary sight:

Equation (8) now represents a non-linear system of equations in three unknowns, the solution of which is generally not given in a closed form. An exact solution can only be found numerically, but depends heavily on the choice of "good" initial conditions and is therefore not necessarily given. If you are limited to small angles of sight when harmonizing, then there are various simplifications of equation (8). Using a truck of approx. 10 m length and 4 m height as a rough estimate, the following would result for the orders of magnitude of the expected squint angle:

It is therefore justified to replace the Kosi nusterme by 1 and the Sinusterme by their argument in equation (8). If you also use the already determined values of (x, y, z) ^T , you get the following system of equations:

The sizes searched for can be extracted from this:

L '' = (d _El - z) sinθ _M + (L - ΔL) cosθ _M (11a)

x, y, and z are known from equations (3a, 3c and 3d). The calculate The squint angle ensures correct supply of the parallelization unit with input data, however, the calculated commanded Seeker head gimbal still for the seeker head replica or the on be processed because the search head replica or the Instruction processor operated on one image level with translations and this only converted into angles. The order is for translatory movements irrelevant, but not for rotations like those in the seeker head gimbal be carried out. The conversion of search head angles in-for the search Head replica or the matching processor (AP) suitable sizes in the following briefly.

The transformation of a vector in the system of the seeker head imitation into the system of the sight is carried out by the rotations θ _SK (θ _SK = angle of the thrower position with respect to the helicopter) (θ _LF + θ _M = placement of the seeker head or the seeker head with respect to the Helicopter, θ _LF = harmonization roll angle between the launcher and the vising flange in elevation), θ _{SL, k} (commanded angle of the seeker head launcher in elevation) and ψ _{SL, k} (commanded angle of the seeker head launcher in azimuth) and a translation (see equation (5)).

The following equations are multiplied from equation (12a) or (12b):

x-ΔL = L '''(cos (θ _SK + θ _{SL, k} ) cosψ _{SL, k} ) (13a)
y-sign (d _Az ) d _Az = L '''sinψ _{SL, k} (13b)
zd _El = -L '''(sin (θ _SK + sinθ _{SL, k} ) cosψ _{SL, k} ) (13c)

From the requirement x = L -ΔL at the location of the target position it follows:

z = - (L - ΔL) tan (θ _SK + θ _{SL, k} ) + d _El (14d)

The suitable angles for a target seeker replica or the instruction processor that the fire control computer (FCC) has to transfer are then determined as follows:

ψ _Sl , θ _SL = commanded azimuth or elevation angle of the seeker head camera with respect to the launcher.

The briefing processor (AP) delivers the harmonization measured angular displacements back: Δψ AP | measured, Δθ AP | measured, Δϕ AP | measured, where Understand the determined stores as the difference between the target value and the actual value. Now you do not know in what proportions during the harmonization test the harmonization errors are broken down quantitatively, so that one absolutely can be justified on the assumption that only the visor the errors produced (position of the target in the sighting image = actual value, position of the Target in the search head replica image = setpoint). The roll percentage (i.e. the roll angle between the turret and the sight flange) Δϕ AP | should be measured as described above requests not to be considered further. The further is thus limited Analysis of the azimuth or elevation angle.  

Since the angular errors in the sighting image (flat coordinate system) were determined, they still have to be transformed into corresponding gimbal angles (spherical coordinates) taking into account the rotation sequence of the gimbal frame. This is done by the fire control computer measuring the angles Δψ AP | measured by the instruction processor or Δθ AP | measured first in
Converts lengths Δy or Δz and uses them to calculate the appropriate gimbal angles using equation (2). The following applies analogously to equations (15a) and (15b):

This results in:

The relationship between Δy and Δz with the gimbal angles follows from equations (3c) and (3 d):

Since the expected angular displacements will probably be very small, you can start with:

Δψ _VF , Δθ _VF «1, cosΔψ _VF ≈ 1, cosΔθ _VF ≈ 1, sinΔψ _VF ≈ Δψ _VF and sinΔθ _VF ≈ Δθ _VF . This gives the above system of equations the following form:

The resolution according to the gimbal angles gives:

The values from equations (17a) and (17b) are to be used for Δy and Δz. Since the instruction processor measured values are already available in the system of the visor flange, no further transformation is required. One only has to note that the correction values should be inverse to the error stores determined. The following therefore applies to the correction values of the harmonization angle:

Δψ _LF = -Δψ _VF (21a)
Δθ _LF = -Δθ _VF (21b)

The fire control computer must be the last step in the harmonization procedure save the values of equations (21a) and (21b).

Claims (8)

1. A method for preparing the fully automatic harmonization of the lines of sight of the visor and seeker head in a weapon system set up on an aircraft, comprising the steps:
Aligning a visor of an aircraft standing on the ground to a target point,
Align a search head to the same target point,
Registering and storing the deviations that occur in this case by an image processing unit as correction values in later use,
Determination of the control angle for the alignment of the seeker head in a fully automatic manner by bringing the lines of sight of the sight and seeker head to the target, and thus the correction values of the harmonization angles. 2. The method according to claim 1, characterized in that the fully automatic determination of the control angle for the alignment of the seeker head comprises the following steps
based on the measurement configuration using geometric relations:
Determining the input variables for a parallelization unit,
Processing the input variables for the parallelization unit in a processing device, such that instead of parallelization of the lines of sight, convergence of the lines of sight is achieved, so that the output values of the parallelization unit, ie the control angle, align the line of sight of the seeker head to the target at the intended distance until the line of sight of the seeker intersects with the line of sight of the sight in the target. 3. The method according to claim 1 or 2, characterized by the further step after determining the control angle, save the correction values the harmonization angle by the fire control computer. 4. The method according to any one of claims 1 to 3, characterized in that the correction values of the harmonization angles result from the following formulas:
in which
with: ψ _LF or θ _LF harmonization angle in azimuth or elevation between turret and visor flange,
Δψ _LF or Δθ _LF correction value for ψ _LF or θ _LF , ψ _VF or θ _VF angle between the optical axis (OAV) or sighting camera and the sight flange in azimuth or elevation,
Δψ _VF or Δθ _VF correction value for ψ _VF or θ _VF
θ _M angle of the visor mast tilt,
L distance sight - target and
Δψ AP | measured, Δθ AP | measured measured angular displacements in azimuth or elec tion. 5. Device for preparing the fully automatic harmonization of the lines of sight of the sight and seeker head in a weapon system set up on an aircraft, comprising:
a device for aligning a visor of an aircraft standing on the ground to a target point,
a device for aligning a search head to the same target point,
an image processing unit for registering and storing the deviations that occur as correction values in later use and
a device for fully automatic determination of the control angle for the alignment of the seeker head, which brings the line of sight of the sight and seeker head to the target, and thus the correction values of the harmonization angle. 6. The device according to claim 5, characterized in that the device for fully automatic determination of the control angle for the alignment of the seeker head comprises the following devices
a device that determines the input variables for a parallelization unit based on the measurement configuration by means of geometric relations,
a processing device for processing the input variables for the parallelization unit, the processing device processing the input variables in such a way that convergence of the lines of sight is achieved instead of parallelization of the lines of sight, so that the output values of the parallelization unit, ie the control angle, the line of sight of the seeker head align the target at the intended distance until the line of sight of the seeker intersects with the line of sight of the sight in the target. 7. The device according to claim 5 or 6, characterized in that the fire control computer for storing the correction values of the Harmo is formed after the determination of the control angle. 8. Device according to one of claims 5 to 7, characterized in that the parallelization unit determines the correction values of the harmonization angle from the following formulas:
With:
ψ _LF or θ _LF harmonization angle in azimuth or elevation between the turret and the sight flange,
Δψ _LF or Δθ _LF correction value for ψ _LF or θ _LF ,
ψ _VF or θ _VF angle between the optical axis (OAV) or visor camera and the visor flange in azimuth or elevation,
Δψ _VF or Δθ _VF correction value for ψ _VF or θ _VF
θ _M angle of the visor mast tilt,
L distance sight - target and
Δψ AP | measured, Δθ AP | measured measured angular displacements in azimuth or elevation.